Gold Fields

Tarkwa gold mine - Mineral Resources and Mineral Reserves

The year-on-year Mineral Resources and Mineral Reserves have changed by -5% and -3% respectively, as a result of mining depletion, resource model and mine design changes, inclusions and cost input updates.

Stockpile tonnage and grade estimates are based on accumulations of estimated tonnage and grades trucked throughout the history of the mine, and are therefore considered to be reasonably accurate. However, the grades and tonnages are discounted by 5% for processing purposes, as experience has shown that this is realistically achievable when reclaiming a stockpile. Unless otherwise stated, all Mineral Resources and Mineral Reserves are quoted as 100% managed and are not attributable with respect to ownership.

Mineral Resources

The Mineral Resource and Mineral Reserve estimates have been updated using the current Gold Fields planning gold price of US$1,400/oz and US$1,200/oz respectively and reported in accordance with the SAMREC Code. The surface sources include stockpiles that are supported by adequate sampling, and are thus classified as Measured Mineral Resources, plus the South Heap Leach material, which is classified as Indicated.

Mineral Resources are quoted at an appropriate in situ economic cut-off grade, with tonnages and grades based on the resource block model. They also include estimates of any material below the cut-off grade that is required to be mined in order to extract the complete pay portion of the Mineral Resource.

Mineral Resource classification

	Tonnes (kt)					Grade (g/t)					Gold (koz)
Classification	Dec 2017	Dec 2016	Dec 2015			Dec 2017	Dec 2016	Dec 2015			Dec 2017	Dec 2016	Dec 2015
Open pit and underground
Measured	58,700	66,833	70,439			1.45	1.47	1.47			2,741	3,160	3,324
Indicated	108,342	110,820	117,029			1.33	1.33	1.33			4,634	4,746	5,015
Inferred	5,497	5,577	4,752			1.18	1.17	1.13			209	210	172
Total in situ	172,538	183,230	192,220			1.37	1.38	1.38			7,584	8,116	8,511
Surface
Measured stockpiles	12,245	8,440	6,588			0.77	0.76	0.72			303	207	152
South Heap Leach (Indicated)	59,977	59,977	59,977			0.40	0.40	0.40			771	771	771
Total surface	72,222	68,416	66,565			0.46	0.44	0.43			1,074	978	924
Grand total	244,760	251,646	258,785			1.10	1.12	1.13			8,658	9,094	9,435

Mineral Resource classification per mining area

	Measured				Indicated				Inferred				Total Mineral Resource
Open pit	Tonnes (kt)	Grade (g/t)	Gold (koz)		Tonnes (kt)	Grade (g/t)	Gold (koz)		Tonnes (kt)	Grade (g/t)	Gold (koz)		Tonnes (kt)	Grade (g/t)	Gold (koz)
Akontansi	20,465	1.29	847		82,409	1.28	3,394		4,411	1.10	157		107,285	1.28	4,398
Kottraverchy	9,982	1.66	533		71	1.01	2			—			10,053	1.66	535
Pepe/Mantraim	10,042	1.43	462		5,887	1.18	223		561	1.44	26		16,490	1.34	711
Teberebie	18,211	1.54	899		19,974	1.58	1,015		525	1.57	26		38,710	1.56	1,940
Total open pit	58,700	1.45	2,741		108,342	1.33	4,634		5,497	1.18	209		172,538	1.37	7,584
Surface
Spent Ore (South Heap Leach)	—	—	—		59,977	0.40	771		—	—	—		59,977	0.40	771
Surface stockpiles	12,245	0.77	303		—	—	—		—	—	—		12,245	0.77	303
Total surface	12,245	0.77	303		59,977	0.40	771		—	—	—		72,222	0.46	1,074
Grand total	70,945	1.33	3,044		168,319	1.00	5,405		5,497	1.18	209		244,760	1.10	8,658

Modifying factors

• The Measured and Indicated Mineral Resources are inclusive of those Mineral Resources modified to produce Mineral Reserves in the LoM plan
• All Mineral Reserves are quoted in terms of RoM grades and tonnages as delivered to the metallurgical processing facilities and are therefore fully diluted
• Unless otherwise stated, all Mineral Resources and Mineral Reserves are quoted as 100% managed and are not attributable with respect to ownership
• Mineral Resources and Mineral Reserves undergo regular internal and/or external audits, and any issues identified are rectified at the earliest opportunity

					December
	Units		2017		2016		2015
Mineral Resource parameters
Mineral Resource gold price	US$/oz		1,400		1,400		1,500
Cut-off for mill feed	g/t		0.37		0.4		0.38
Mineral Reserve parameters
Mineral Reserve gold price	US$/oz		1,200		1,200		1,300
Cut-off for mill feed	g/t		0.44		0.47		0.45
Mining recovery factor (open pit)	%		100		100		100
Strip ratio (waste:ore)	ratio		5.0		5.1		5.4
MCF	%		98		98		98
Dilution open pit1	cm		30/20		30/20		30/20
Plant recovery factor - CIL	%		97.0		97.0		97.0
CIL processing capacity	Mtpa		13.7		13.5		13.5

¹ Refers to 30cm hangingwall and 20cm footwall dilution respectively

Grade tonnage curve

Grade tonnage curve for the entire open pit Mineral Resource is presented below

	Grade tonnage curve - Surface

Mineral Reserves

The Mineral Reserve estimate for Tarkwa gold mine is based on the development of appropriately detailed and engineered LoM plans. All design and scheduling work is undertaken to an applicable level of detail by experienced engineers using mine-planning software. The planning process incorporates realistic modifying factors and the use of appropriate cut-off grades, geotechnical criteria, mining fleet productivities and other techno-economic investigations.

Mineral Reserve statements include only Measured and Indicated Mineral Resources modified to produce Mineral Reserves contained in the LoM plan. This declaration is based on the premise that all the ore will be treated through the CIL plant.

Mineral Reserve classification

	Tonnes (kt)					Grade (g/t)					Gold (koz)
Classification	Dec 2017	Dec 2016	Dec 2015			Dec 2017	Dec 2016	Dec 2015			Dec 2017	Dec 2016	Dec 2015
Open pit
Proved	40,464	53,542	63,266			1.26	1.28	1.30			1,644	2,200	2,635
Probable	82,015	74,150	81,506			1.21	1.22	1.22			3,188	2,903	3,187
Total open pit	122,479	127,692	144,773			1.23	1.24	1.25			4,832	5,104	5,822
Surface
Proved stockpiles	12,245	8,440	6,588			0.77	0.76	0.72			303	207	152
South Heap Leach (Probable)	59,977	59,977	59,977			0.40	0.40	0.40			771	771	771
Total surface	72,222	68,416	66,565			0.46	0.44	0.43			1,074	978	924
Grand total	194,701	196,108	211,338			0.94	0.96	0.99			5,906	6,082	6,746

Mineral Reserve classification per mining area

	Proved					Probable					Total Mineral Reserve
Mining area	Tonnes (kt)	Grade (g/t)	Gold (koz)			Tonnes (kt)	Grade (g/t)	Gold (koz)			Tonnes (kt)	Grade (g/t)	Gold (koz)
Open pit
Akontansi	14,402	1.09	504			61,334	1.14	2,250			75,735	1.13	2,753
Kottraverchy	4,413	1.39	198			—	—	—			4,413	1.40	198
Pepe/Mantraim	6,467	1.30	271			1,162	1.05	39			7,629	1.26	310
Teberbie	15,183	1.38	672			19,519	1.43	899			34,702	1.41	1,570
Total open pit	40,464	1.26	1,644			82,015	1.21	3,188			122,479	1.23	4,832
Surface
Spent ore (SHL)	—	—	—			59,977	0.40	771			59,977	0.40	771
Surface stockpiles	12,245	0.77	303			—	—	—			12,245	0.77	303
Total surface stockpiles	12,245	0.77	303			59,977	0.40	771			72,222	0.46	1,074
Grand total	52,709	1.15	1,947			141,991	0.87	3,959			194,701	0.94	5,906

Mineral Resource and Mineral Reserve reconciliation year-on-year

Factors that affected Mineral Resource year-on-year		Factors that affected Mineral Reserve year-on-year
Depletion by mining		Depletion by mining
Updated economic factors		Improved costs
Mineral Resource model updates, predominately at Akontansi and PAMTA		Mineral Resource model updates
		Re-optimisation/re-engineering of pit designs at Teberebie and Akontansi

Mineral Resource reconciliation (Gold – koz)		Mineral Reserve reconciliation (Gold – koz)

Mineral Reserve sensitivity

The Mineral Reserve sensitivity has been derived from the application of the relevant cut-off grades to individual grade tonnage curves of the optimised pit shells for the open pits.

The Mineral Reserve sensitivities are not based on detailed depletion schedules and should be considered on a relative and indicative basis only. The following graphs indicate the Managed Mineral Reserve sensitivity at -15%, -10%, -5%, base (US$1,200/oz), +5%, +10%, and +15% to the gold price.

	Mineral Reserve sensitivity (Gold – Moz)